In Germany there are about 150,000 blind persons and about 500,000 visually impaired persons. Worldwide there are about 160 millions blind or visually impaired persons. Ordinary activities, such as shopping at supermarket or use of public transport, are often an insurmountable obstacle for these persons since most part of information relevant for such activities is available only in written form. A general technical approach for overcoming such problems is the provision of computer-based assistance systems which can be used as reading aid by blind or visually impaired persons.
However, until now most available reading systems do not support mobility and, therefore, have limited usefulness in everyday life. Despite of apparent great demand until now advancing miniaturization of computer technology has merely used sporadic for development of mobile reading devices for blind or visually impaired persons. In few cases in which this has been done such assistance systems require a considerable degree of assistance and handling of a user to offer a sufficient degree of assistance even under partly suboptimal environmental conditions.
In currently available reading devices the blind or visually impaired person has to put the object containing text into a scanner or has to move a capturing device such as a digital camera or a portable scanner across the object to be detected. However, this is not always possible since objects such as timetables, packages, books or the like can partly not be scanned with sufficient quality. If a digital camera or a portable scanner is used the user has to bring the objects to be detected to the digital camera or the portable scanner or has to bring the digital camera or the portable scanner to the objects to be detected. In mobile use this is only possible in a limited manner since the user on the one hand does not always know where a object to be detected is present and on the other hand does not always have hands free to perform required actions
Reading devices for blind or visually impaired persons are often available in libraries and are also sold for use at home. However, often the operation of buttons and switches is an insurmountable obstacle for blind or visually impaired persons.
From WO 2005/096760 A2 there are known reading devices for blind or visually impaired persons. In more detail, this document discloses portable reading devices and corresponding methods in general form and also discloses which diversity of technical requirements must be considered in designing such portable reading devices and which diversity of approaches are available for a promising product.
However, this document is fully silent about how to put the technical requirements into practice and how to realize an overall working technical solution from such technical requirements. Furthermore, the specific technical requirements are directed to portable reading devices which require assistance from a user in a considerable manner.